scholarly journals Technologies of refining of aluminum alloys by gas blowing

Author(s):  
M. A. Sadokha ◽  
A. A. Andrushevich

The results of the analysis of various methods of refining aluminum alloys from dissolved gases and non-metallic inclusions are presented. The influence of a number of technological features of each method on the quality of the melt has been studied. Examples of equipment for the implementation of processes are presented. To analyze the effectiveness of the use of various technologies for refining aluminum alloys, their ranking was carried out. The results of the analysis are in correlation with the trends in the spread of various processes for the refining of aluminum alloys in foundries. It is shown that blowing the melt with inert gases through a rotating impeller is the most effective in terms of a set of indicators in comparison with other methods.

2019 ◽  
Vol 91 (10) ◽  
pp. 7-15
Author(s):  
Tomasz Piwowarczyk ◽  
Marcin Korzeniowski ◽  
Dawid Majewski

This article explores the possibilities of using non-destructive ultrasonic techniques to analyze the quality of lapped braze-welded joints. The tests were performed for 4 material groups (DC03+ZE steel and X5CrNi18-19 steel, aluminum alloys AW-5754 and AW-6061, titanium Grade 2 and copper Cu-ETP). As part of the work, additional materials and joint processes and its parameters were selected (TIG, MIG, laser). The quality of joints was monitored using scanning acoustic microscopy. Based on the A-scan andC-scan images, potential joints imperfections were determined. The possibilities of using advanced ultrasonic techniques to analyze the quality of braze joints was assessed.


Author(s):  
Н.В. Астахов ◽  
А.В. Башкиров ◽  
О.Ю. Макаров ◽  
А.А. Пирогов ◽  
А.С. Демихова

Обеспечение надежности и качества радиоэлектронных средств и приборов - это одна из главных задач в процессе проектирования новых устройств. Благодаря высокому качеству паяных соединений увеличивается срок службы электронных изделий, а также их безотказность в процессе эксплуатации и ремонтопригодность. Также нужно не забывать об экологической безопасности производимых устройств. В связи со всем вышеизложенным наиболее перспективно проводить исследования и искать практические решения возникающих трудностей в сфере технологий, в которых используются бессвинцовые припои, что позволит соблюсти современные требования к электронной аппаратуре. Кратко изложены основные последствия и проблемы применения чисто бессвинцовой пайки, рассмотрены проблемы применения смешанной технологии пайки и исследование эффекта роста оловянных «усов». Сделан вывод о том, что избежать большинства дефектов помогает применение активных флюсов, сохраняющих свои свойства при высоких температурах, пасту необходимо выбирать с тем условием, что в ее составе не должно быть канифоли, которая начинает активно выделяться в виде газа при повышении температуры, следует также верно подбирать температурный профиль пайки. Среди финишных покрытий лучше всего себя зарекомендовали иммерсионное серебро и никель-золото. Применение в припое в качестве заменителей свинца таких металлов, как висмут и индий существенно повышает стоимость припоев. Отмечается, что хорошие показатели имеют припои с содержанием цинка, однако цинк приводит к невозможности долгосрочного хранения паяльных паст, повышению оксидирования, необходимости пайки в среде инертных газов и с применением активных флюсов Ensuring the reliability and quality of radio-electronic equipment and devices is one of the main problems in the process of designing new devices. Due to the high quality of soldered joints, the service life of electronic products increases, as well as their reliability during operation and maintainability. It is also necessary not to forget about the environmental safety of the manufactured devices. In connection with all the above, it is most promising to conduct research and look for practical solutions to the emerging difficulties in the field of technologies that use lead-free solders, which will allow us to meet modern requirements for electronic equipment. The article briefly describes the main consequences and problems of using pure lead-free soldering, the problems of using mixed soldering technology, and the study of the effect "whiskers". Use of active fluxes that retain their properties at high temperatures helps to avoid most defects, the paste should be chosen with the condition that it should not contain rosin, which begins to actively emit as a gas when the temperature rises, and the temperature profile of soldering should also be correctly selected. Among the finishing coatings, immersion silver and nickel-gold proved to be the best. The use of metals such as bismuth and indium in solder, as lead substitutes, significantly increases the cost of solders. The article also notes that solders with a zinc content have good indicators but zinc leads to the impossibility of long-term storage of soldering pastes, increased oxidation, the need for soldering in an environment of inert gases and with the use of active fluxes


2020 ◽  
pp. 55-57
Author(s):  
M.G. Galkin ◽  
A.S. Smagin ◽  
A.S. Pupyireva

An algorithm for the development of a mathematical model of cutting processing, as a multifactorial process, which determines the influence of significant parameters of the cutting mode on the roughness of the processed surface, is proposed. In the development of the algorithm, the method of extreme experimental design is used. Keywords cutting, mode, manufacturing process, surface roughness, mathematical model. [email protected]


2011 ◽  
Vol 689 ◽  
pp. 343-349
Author(s):  
Zhi Hui Zhang ◽  
Shu Feng Liu ◽  
Ze Ming Sun ◽  
Xiao Dong Yan

The relationship between microstructure and anodic oxidation film on 6061 aluminum alloy dedicated to plasma etcher were mainly studied by OM, SEM and TEM. The results show that the quality of anodic oxidation film has close relationship with the microstructure of materials, the distribution of element and the morphology of secondary phases. The microstructure of foreign 6061 aluminum alloy is uniform, and there are not obviously segregation and cavity. Two kinds of secondary phases disperse over the grain, one is rich-Fe phase, and the other is Mg2Si. Certainly there are also few secondary phases distributing along the grain boundary. The sizes of all secondary phases are almost below 5mm. The size of rich-Fe phases in homemade aluminum alloys are about from 2mm to 15mm, these big-size phases will bring pin-hole defects, which form some channels sending F+ etc. into the matrix of aluminum alloy, then not only the equipment will be destroyed at last, but also products will be polluted. The evaluation on microstructure of aluminum alloy will provide scientific basis for nationalization of plasma etcher.


2014 ◽  
Vol 216 ◽  
pp. 267-272 ◽  
Author(s):  
Erika Ardelean ◽  
Marius Ardelean ◽  
Teodor Hepuț ◽  
Florin Drăgoi

The existence of gases in the solid metals (hydrogen and nitrogen) assumes the presence of these gases in metals even before solidification, respectively in the elaboration, secondary treatment and casting phases. Usually, great amounts of gases dissolved in steels can be detected, between 3.5-8ppm for hydrogen and 0.02-0.03% for nitrogen, respectively. There are also cases when the purpose is to alloy with nitrogen, this being the case of austenitic stainless steels where the nitrogen content can reach 0.5% using ferrochromium or ferromanganese alloyed with nitrogen in 3-5.5 %. The main method of removing these gases is bubbling with inert gases and /or treating the steel in a vacuum facility. The paper presents a study regarding increasing the removal efficiency of nitrogen from the liquid steel by changing the bubbling parameters (flow, pressure, duration) but also the basicity of the refining slag. The equations of the regression surface and the identified fields are of a real help for the technologists, allowing quick decisions but they are also important for the quality of the metallic products [.


2013 ◽  
Vol 13 (4) ◽  
pp. 39-42 ◽  
Author(s):  
S. Gnapowski ◽  
Y. Tsunekawa ◽  
M. Okumiya ◽  
K. Lenik

Abstract This experiment utilized five Aluminum alloys with silicon content percentages of 7, 10, 12.6, 14.5 and 17(wt)%. Ultrasonic vibration was applied to improve the quality of aluminum alloys. Sono-solidification, in which ultrasound vibrations are applied to molten metal during its solidification, is expected to cause improved mechanical properties due to grain refinement. Observed by microstructure photographs was that grains became smaller and their shapes more regular. Using ultra sound solidification α Al appeared during ultrasound treatment the eutectic solidification time was longest around 10% compared with same condition experiment without ultrasound treatment.


2016 ◽  
Vol 710 ◽  
pp. 155-159
Author(s):  
Mariem Zoghlami ◽  
Mohammad Jahazi ◽  
Victor Songmene

Since the invention of the friction stir welding, several studies have been conducted to understand the influence of process parameters on the microstructural, thermal and mechanical characteristics to improve the weld quality. Banded structures better known under the name of "onion rings" are one of phenomena that appear in the microstructure during this process. The welding parameters leading to their appearance as well as their effect on the quality of the joint are still subject to much research with different conclusions. In this context, the objective of this research work is to determine various characteristics of the ‘onion rings’ and correlate them to processing conditions.


Author(s):  
M. A. Sadokha

The results of studies of obtaining complex castings from aluminum alloys using the self-filling method are presented. The influence of a number of technological parameters (pouring time, chill cooling mode, the use of self-filling, etc.) on the quality of the resulting piston castings has been studied. The optimal time for filling the chill mold was determined when casting pistons. It is shown that the chill mold cooling mode has a significant impact on the quality of castings.


2021 ◽  
Vol 12 (2) ◽  
pp. 139-145
Author(s):  
G. A. Gusakov ◽  
G. V. Sharonov

Improving the technology of diamond turning of aluminum alloys is of great importance for expanding the application areas of metal-optical products based on aluminum in aerospace technology. The aim of this work was to study the effect of surface inhomogeneities of the initial aluminum alloy substrates on their optical and mechanical characteristics and to determine ways of improving the quality of aluminum reflector mirrors manufactured using nanoscale single point diamond turning. The investigated reflector mirrors were made from AMg2 aluminum alloy. The optical surface treatment was carried out on a precision turning lathe with an air bearing spindle using a special diamond cutter with a blade radius of ≤ 0.05 μm. The analysis of the surface structure of the AMg2 alloy substrates was carried out by scanning electron microscopy / electron microprobe. The quality control of the surface treatment of the manufactured reflector mirrors was carried out by atomic force microscopy. The reflectivity and radiation resistance of these samples were also investigated.It is shown that an important problem in the manufacture of optical elements from aluminum alloys is the inhomogeneity of the structure of the initial material, associated with the presence of intermetallic inclusions. Heat treatment of the AMg2 alloy substrates at T ≥ 380 °C makes it possible to improve the quality of surface and the radiation resistance of aluminum mirrors both by removing mechanical stresses and by partially homogenizing the starting material. The optimum is heat treatment at the maximum allowable temperature for the AMg2 alloy T = 540 ºС, as a result of which there is a complete disappearance of intermetallic inclusions with an increased magnesium content. The use of high-temperature heat treatment of AMg2 alloy substrates allows, in comparison with unannealed samples, to reduce the surface roughness from 1.5 to 0.55 nm, to increase the reflectivity of mirrors at a wavelength of 1064 nm from 0.89 to 0.92, and to increase the laser damage threshold from 3.5 to 5 J / cm2.


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